Transcript

The northern hemisphere goes through a 21,000 year cooling and warming cycle that results in periodic Ice Ages. We’re now well into cooling phase of that cycle. But new research based on core samples of Arctic lake bottoms reveal that while temperatures had been dropping every decade of the past 2000 years, in the year 1900 they began shooting up. And the past ten years, since 1999, were the warmest ever. The study is the latest evidence that the buildup of human-produced carbon dioxide in the 20th century has thrown earth’s climate cycles into reverse.

In other environmental science news, a consortium of research institutions is building a series of undersea observatories in key locations around the world. The stations will monitor large scale phenomena in our oceans, including temperature, currents and ocean chemistry. I’m Bob Hirshon for AAAS, the Science Society.